Polynitro alcohols



United States Patent Ofiice Patented Sept. 19, 1961 This invention relates to new and useful polynitro alcohols and to a method for their preparation. In particular, this invention is directed to polynitro alcohols having the general formula:

wherein A is either an alkylene or nitroalkylene radical, and R is a lower nitroalkyl radical.

The polynitro alcohols of our invention find valuable use as intermediates in the preparation of high explosive compounds. For example, 3,5 ,5,5-tetranitro-3-aza-lpentanol can be condensed with methyl isocyanate according to the method disclosed in assignees copending United States patent application Serial No. 482,410, filed January 17, 1955, to yield N-methyl-N-3,5,5,5-tetranitro-3-azapentyl carbamate. The compounds thus prepared are useful as high explosives and can be used in any conventional explosive missile, projectile, rocket, or the like, as the main explosive charge. An example of such a missile is disclosed in United States Patent No. 2,470,162 issued May 17, 1949. One way of using the high explosives in a device such as that disclosed in United States Patent No. 2,470,162 is to pack the crystalline explosive in powder form into the warhead of the missile. Alternatively, the crystals can be first pelletized and then packed. A charge thus prepared is sufiiciently insensitive to withstand the shock entailed in the ejection of a shell from a gun barrel or from a rocket launching tube under the pressure developed from ignition of a propellant charge, and can be caused to explode on operation of an impactor time-fuse mechanism firing a detonating explosive such as lead azide or mercury fulminate.

It is well known that acyl halides may be reduced to their corresponding alcohols with reducing agents such as lithium aluminum hydride, and hydrogen in the presence of a catalyst. However, these conventional reducing agents all possess such strong reducing properties that the destruction of functional groups, such as aliphatic nitro groups, usually accompanies the reduction of the carbonyl group. This method is further complicated by the sensitivity of nitro groups to basic media, hence these reducing agents, although capable of effecting the reduction, nevertheless have many undesirable features making it advantageous to find some more convenient method.

We have now found that polynitro alcohols can be prepared from their corresponding acyl halides by reduction with sodium borohydride in accordance with the general reaction scheme set forth below:

wherein A is an alkylene or nitroalkylene radical, R is a lower polynitroalkyl radical and X is a halogen radical.

The reduction is eflected by adding a solution of a nitrocontaining acyl halide to a suspension of sodium borohydride.

Optimum results are obtained using a suspension of powdered sodium borohydride, about 200% excess, in an inert solvent such as dioxane.

1,4-dioxane is the preferred solvent due to its inert behavior and volatility. Any inert organic solvent can be used such as 2,4-dimethylsulfolane; however, dioxane is preferred since it can be separated from the product with greater ease.

The compounds thus produced are obtained in a relatively pure form from the reaction mixture by hydrolyzing the sodium borohydride and its oxidation products in the aqueous phase, with a mineral acid, and recovering the product by crystallization, extraction or distillation from the non-aqueous phase.

The following example is presented to more clearly illustrate our invention. This example is presented purely as a means of illustration, and does not in any way define either the limits or the scope of our invention.

EXAMPLE I Preparation of 3,5,5-rrinitro-3-aza-1-hexanol A reactor was charged with 35 ordinary glass marbles, gm. finely powdered sodium borohydride and 2 liters of absolute dioxane. With stirring, 1500 ml. of dioxane were removed by distillation, at which time the distillate was no longer basic. After cooling to room temperature, a solution of 1.5 ml. of glacial acetic acid in 15 ml. of dioxane was added dropwise. While maintaining the internal temperature at about 24 C. a solution of .3 mole 3,5,5-trinitro-3-aza-l-hexanoyl chloride in 600 ml. of dioxane was added dropwise over a period of about 2 hours. The mixture became viscous and 300 ml. of dioxane were added at the mid-point. The mixture gradually became thinner over a period of time. The reaction was allowed to proceed for 4 hours, after which time the reaction mixture was cautiously poured into a stirred mixture of 400 ml. of cone. hydrochloric acid and excess ice. The final mixture had a volume of about 8 liters. During the hydrolysis an oil was isolated by filtration, and the aqueous dioxane filtrate extracted with ether and benzene and crystallized from methylene chloride. The product was dissolved in a mixture of absolute ethanol, benzene and cyclohexane and treated with 'decolorizing carbon. The solution was cooled, resulting in the fiormation of crystals which were isolated and washed with a small amount of cold solvent mixture and dried. The product, 3,5,5-trinitro-3-aza-l-hexanol was recovered in an amount corresponding to the 82% of theoretical, and had a melting point of 5960 C. The elemental analysis of the prodnot was as follows:

Calculated: Percent C, 25.21; percent H, 4.23; percent N, 23.53. Found: Percent C, 25.48; percent H, 4.06; percent N, 23.78.

The polynitro acid halides used as starting materials in the practice of our invention are prepared from their corresponding acids by conventional means; for example, by their reaction with a thionyl halide. The acids are prepared by the reaction of a nitroalkane and a labile hydrogen-containing acid. For example, 4,4,4-trinitro-1-butanoic acid is prepared by reacting nitroform and acylic acid. Alternatively, the acids can be prepared by reacting a nitroalkane and a labile hydrogen-containing aldehyde followed by oxidation of the carbonyl group to the desired acid.

Other members of the new class of compounds of our invention can be prepared by the method disclosed above; for example, 3,5,5,S-tetranitro3-aza-l-pentanol is prepared by reducing 3,5,5,5-tetranitro-3-aza-l-pentanoyl chloride with sodium borohydride; 3,3,5,7,7,7-hexauitro-' S-aza-l-heptanol is prepared by reducing 3,3,5,7,7,7-hexanitro-S-aza-l-heptanoyl chloride with sodium borohydride; and 3,3,5,7,7-pentanitro-5-aza-l-octanol is prepared by reducing 3,3,5,7,7-pentanitro-S-aza-l-octanoyl chloride with sodium borohydride. It will be appreciated by those skilled in the art that other members of this new class of compounds can be prepared in the same manner simply by reacting appropriate starting materials. It is preferred in the practice of our invention to utilize polynitro acid chlorides as starting materials for reasons of cost and convenience, however it should be understood that any of the acid halides can be used. It will also be appreciated that reaction temperatures are not critical in the practice of our invention, and that both higher and lower temperatures and conditions can be used if desired without affecting the course of the reaction.

We claim:

1. As compositions of matter, the polynitro alcohols having the formula:

wherein R is a lower nitroalkyl radical and A is a radical selected from a. group oonsistingof lower alkylene and lower nitroalkylene radicals.

2. As compositions of matter, having the formula:

wherein R is a lower polynitro alkyl radical and A is a lower alkylene radical.

3. As compositions of matter, having the formula:

the polynitro alcohols N01 N: BAG-JJ-CHI-N-CHiCH'OH 5. As a composition of matter, 3,S,5,$-tetranitro-3-azal-pentanol having the structural formula:

6. As a composition of matter, 3,3,5,7,7,7-hexanitro-5- aza-l-heptanol having the structural formula:

7. As a composition of matter, 3,3,5,7,7-pentanitro-5- aza-l-octanol having the structural formula:

8. The method of preparing polynitro alcohols having the formula:

N0] RCH2Ii-A-CH2OH which comprises reducing a polynitro acid halide having the formula:

E-CHrlk-uA-iiX with sodium borohydride wherein R is a lower nitroalkyl radical and A is a radical selected from a group consisting of lower alkylene and lower nitroalkylene radicals, and X is a halogen radical.

9. The method of claim 8 wherein the reaction is conducted in the presence of an inert organic solvent.

10. The method of claim 8 wherein the reaction is conducted in the presence of 1,4-dioxane.

11. The method of preparing 3,5,5-trinitro-3-aza-l-hexanol which comprises reducing 3,5,5-trinitro-3-aza-hexanoyl chloride with sodium borohydride.

12. The method of preparing 3,5,5 ,S-tetranitro-B-aza-lpentanol which comprises reducing 3,5,5 ,5-tetranitro-3- aza-l-pentanoyl chloride with sodium borohydride.

13. The method of preparing 3,3,5,7,7,7-hexanitro-5- aza-l-heptanol which comprises reducing 3,3,S,7,7,7-hexanitro-S-aza-l-heptanoyl chloride with sodium borohydride.

14. The method of preparing 3,3,5 ,7,7-pentanitro-5-azal-octanol which comprises reducing 3,3,5,7,7-pentanitro- S-aza-l-octanoyl chloride with sodium borohydride.

No references cited. 

1. AS A COMPOSITIONS OF MATTER, THE POLYNITRO ALCOHOLS HAVING THE FORMULA 